Abstract
Cucumber (Cucumis sativus L. cv. Mesa) and onion (Allium cepa L. cv. Rijnsburger Heldis) seeds were rapidly aged at 40 °C and 74% relative humidity. Onion seeds were also slowly aged at 40 °C with 15% relative humidity for 11 months and one more month at 28% relative humidity. Significant loss of total and individual phospholipids was an early event during both storage treatments. With slow ageing of onion, loss of phosphatidylcholine occurred several months before loss of viability and vigour was detected. Phosphatidic acid, the lipid product of phospholipase D action, increased during rapid ageing of both cucumber and onion. Phosphatidic acid was present in onion seeds before the ageing treatments and its content remained unchanged in the slowly aged seeds. There was 1600 (cucumber) and 2000 (onion) times more phospholipase D activity (6 × 105 and 2·9 × 105 nmol g−1 d−1 in cucumber and onion, respectively) in crude extracts from non-aged seeds than was required to account for the fastest fall in phospholipids (72, 372 and 144 nmol g−1 d−1 for cotyledons and radicles of cucumber and onion, respectively, over the first 9 d [cucumber] or 1 d [onion] of ageing) and fastest increase in phosphatidic acid (7, 162 and 37 nmol g−1 d−1). How accurate a guide the in vitro activity of phospholipase D was to the in vivo activity was unclear. However, the considerable excess activity seen with the formation of phosphatidic acid supports the proposal that hydrolysis of phospholipids by phospholipase D is a first step in deterioration during ageing. Substantial lipoxygenase activity was also detected (58 × 103 and 54 × 103 nmol g−1 d−1 respectively, for non-aged cucumber and onion seeds). However, the increase in conjugated dienes (an early product of peroxidation) in ageing cucumber seeds was comparatively small (90 nmol g−1 d−1 over 21 d ageing), and increase in malondialdehyde could not be detected, indicating that peroxidation may not have been a major factor in cucumber. The increase in conjugated dienes during rapid ageing of onion seeds was larger (1·5 × 103 nmol g−1 d−1 over days 0–2 of rapid ageing), much greater than the decrease in phospholipid acyl groups (260 nmol g−1 d−1 over days 0–2 of rapid ageing) indicating the occurrence of peroxidation of fatty acids released from reserve as well as from membrane lipids. This higher level of conjugated dienes during onion ageing was the main difference between cucumber and onion, indicating that the level of peroxidation could be an important difference between fast and slow ageing seeds. However, peroxidation is not the only possible deleterious process since hydrolysis of the normal membrane phospholipids to phosphatidic acid increased the content of non-bilayer-forming lipids and this too could be a direct membrane-destabilizing consequence of phospholipase D action during ageing.
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Claims 11
Claim · model-written summary
Rapid ageing caused early phospholipid loss in cucumber and onion seeds.
- Taxon
- Cucumber
Cucumis sativust0 - Treatment
- storage treatmentse0
- Outcome
- total and individual phospholipidse0
- Direction
- losse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant loss of total and individual phospholipids was an early event during both storage treatments.”
t0“Cucumber and Onion Seeds”
Claim · model-written summary
Slow ageing caused phosphatidylcholine loss before onion seed viability and vigour declined.
- Taxon
- onion
Allium cepae0 - Organ / stage
- seedt0
- Outcome
- phosphatidylcholinee0
- Direction
- losse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With slow ageing of onion, loss of phosphatidylcholine occurred several months before loss of viability and vigour was detected.”
t0“Cucumber and Onion Seeds”
Claim · model-written summary
Phosphatidic acid increased during rapid ageing in cucumber and onion.
- Taxon
- cucumberCucumis sativuse0
- Treatment
- rapid ageinge0
- Gene
- phospholipase De0
- Outcome
- Phosphatidic acide0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phosphatidic acid, the lipid product of phospholipase D action, increased during rapid ageing of both cucumber and onion.”
Claim · model-written summary
Phosphatidic acid remained unchanged in slowly aged onion seeds.
- Taxon
- onionAllium cepae0
- Treatment
- slowly agede0
- Outcome
- Phosphatidic acide0
- Direction
- remained unchangede0
- Comparator
- before the ageing treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phosphatidic acid was present in onion seeds before the ageing treatments and its content remained unchanged in the slowly aged seeds.”
Claim · model-written summary
Non-aged cucumber seeds had 1600 times more phospholipase D activity than required for the fastest phospholipid fall.
- Taxon
- cucumberCucumis sativuse0
- Gene
- phospholipase De0
- Outcome
- phospholipase D activitye0
- Direction
- moree0
- Value
- 1600e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was 1600 (cucumber) and 2000 (onion) times more phospholipase D activity”
Claim · model-written summary
Non-aged onion seeds had 2000 times more phospholipase D activity than required for the fastest phospholipid fall.
- Taxon
- onionAllium cepae0
- Gene
- phospholipase De0
- Outcome
- phospholipase D activitye0
- Direction
- moree0
- Value
- 2000e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was 1600 (cucumber) and 2000 (onion) times more phospholipase D activity”
Claim · model-written summary
Lipoxygenase activity was detected in non-aged cucumber and onion seeds.
- Taxon
- cucumberCucumis sativuse0
- Gene
- lipoxygenasee0
- Outcome
- lipoxygenase activitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Substantial lipoxygenase activity was also detected (58 × 103 and 54 × 103 nmol g−1 d−1 respectively, for non-aged cucumber and onion seeds).”
Claim · model-written summary
Conjugated dienes increased only slightly during cucumber seed ageing.
- Taxon
- cucumberCucumis sativuse0
- Outcome
- conjugated dienese0
- Direction
- increasee0
- Value
- 90 nmol g−1 d−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increase in conjugated dienes (an early product of peroxidation) in ageing cucumber seeds was comparatively small (90 nmol g−1 d−1 over 21 d ageing)”
Claim · model-written summary
Malondialdehyde increase was undetectable in ageing cucumber seeds.
- Taxon
- CucumberCucumis sativust0
- Outcome
- malondialdehydee0
- Direction
- could not be detectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increase in malondialdehyde could not be detected”
t0“Cucumber and Onion Seeds”
Claim · model-written summary
Conjugated dienes increased more during rapid onion ageing.
- Taxon
- onionAllium cepae0
- Outcome
- conjugated dienese0
- Direction
- increasee0
- Value
- 1·5 × 103 nmol g−1 d−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in conjugated dienes during rapid ageing of onion seeds was larger (1·5 × 103 nmol g−1 d−1 over days 0–2 of rapid ageing)”
Claim · model-written summary
Phospholipid acyl groups decreased during rapid onion ageing.
- Taxon
- onionAllium cepat0
- Outcome
- phospholipid acyl groupse0
- Direction
- decreasee0
- Value
- 260 nmol g−1 d−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the decrease in phospholipid acyl groups (260 nmol g−1 d−1 over days 0–2 of rapid ageing)”
t0“Cucumber and Onion Seeds”
The same questions in other papers
storage · molecular: metabolites · Cucumis sativus (cucumber)Positive and negative results
4 in the opposite direction
- positive
- positive
- positive
1 paper more in this group
See all 5 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.